<!DOCTYPE HTML>
<html>
	<head>
		<title>IP Address Validation</title>
		<style type="text/css">
			.result_spn
			{
				color:#00ff00;
				font-size:20px;
			}
			.error_spn
			{
				color:#ff0000;
				font-style:italic;
			}
		</style>
		<script language="javascript">
			function validate_ip()
			{
				var chkdate = document.getElementById("ip_txt").value;
				document.getElementById("error").innerHTML="";
				document.getElementById("result").innerHTML="";
				if(document.getElementById("ip_txt").value == "")
				{
					document.getElementById("error").innerHTML="Please enter the IP Address";
					document.getElementById("ip_txt").focus();
				}
				else if(!chkdate.match(/^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/))
				{
					document.getElementById("error").innerHTML="IP Address format is wrong";
					document.getElementById("ip_txt").focus();
				}
				else
				{
					document.getElementById("result").innerHTML="This is Valid IP Address";
				}
			}
		</script>
	</head>
	<body>	
		<form name="frm" id="frm">	
			<div>
				<label for="dob">Enter the IP Address</label>
				<input type="text" name="ip_txt" id="ip_txt"/>
				<span id="error" class="error_spn">*</span>
			</div>
			<div>
				<input type="button" name="check_btn" id="check_btn" value="validate" onclick="validate_ip()"/>
			</div>
			<div>
				<span id="result" class="result_spn"></span>
			</div>
		</form>
	</body>
</html>

O Level Exam : Practical Question

🖥 Output: